Lighter-than-air vehicles, such as aerostats, blimps, balloon, dirigibles, or airships, are used in many different applications, such as near large sporting, entertainment or cultural events, or in large metropolitan areas to provide advertising or to provide high level coverage of the events. Lighter-than-air vehicles are also used in high altitude applications, for the purpose of weather monitoring and/or military surveillance. In such instances, the higher a vehicle can operate translates into an increased amount of area that can be viewed for surveillance purposes and/or weather monitoring. Additionally, lighter-than-air vehicles that possess the ability to operate at altitudes above 50,000 feet are not a hazard to commercial air traffic, are more difficult to detect and/or destroy, can be used for the surveillance of wide areas, and thus can provide a strategic and/or economic advantage.
Typically, high altitude lighter-than-air vehicles are made from laminates of materials that withstand a wide range of temperature variation, ozone degradation, exposure to ultraviolet light and daily expansion and contraction due to the wide temperature variations.
U.S. Pat. No. 6,979,479 teaches a laminate of a liquid crystal polymer fiber yarn layer (VECTRAN®) as an interior surface, an adhesive layer, a polyimide layer, and a polyvinylidene fluoride (PVDF) layer which forms the exterior surface. The polyimide layer functions as a gas barrier for retaining helium or hydrogen. The polyvinylidene fluoride layer provides ozone and ultraviolet light protection.
With regard to fabrics for lighter-than-air vehicles operating at high altitudes it is also typical to have a thin metal coating as one of the layers to reflect most of the incident solar radiation, reduce helium permeation, minimize the effects of lightening strikes, and provide a means for uniform static electric distribution over the hull surface
Given the above, providing logos and/or identification letter and/or numbers for lighter-than-air vehicles can be a problem since such logos, letters and/or numbers must provide identification without significantly affecting the local thermal management properties of the materials used to form the hull portion of such lighter-than-air vehicles. The use of dark letters for contrast is not satisfactory since they will allow localized heat accumulation.